The present invention relates generally to aviation electronics (avionics) systems. More particularly, the present invention relates to implementing and managing avionics functions in avionics systems that include software defined radios.
Avionics onboard an aircraft include communication, navigation and surveillance functions. These functions provide flight crew members with the capability to communicate with ground-based facilities and control the flight of the aircraft in response to flight conditions according to flight plans. Avionics also provide passenger entertainment in airline operations.
In general, prior art avionics systems have included many dedicated pieces of equipment that each provide a function (also referred to as waveform) to give flight crew members the ability to manually or automatically control the flight of an aircraft. Each piece of equipment (or radio) usually operates to some extent independently of the other pieces of equipment in the avionics system and performs a dedicated function throughout the entire flight. Examples of such separate pieces of equipment include a global positioning system (GPS) navigation device, a radio altimeter, a traffic alert collision avoidance system (TCAS) or a voice communication radio. Having separate dedicated pieces of equipment to perform these functions typically adds to the total equipment costs as well as the weight of the aircraft. Furthermore, having numerous separate dedicated pieces of equipment typically takes up much more volume or space, uses more power, requires more total cooling air, etc., than is used having an integrated set of avionics equipment.
Some more recent avionics systems include one or more software defined radios (SDRs) instead of dedicated pieces of equipment. A SDR essentially includes interconnected hardware and software components that are collectively capable of performing one or more avionics communication, navigation or surveillance function. As compared to the combination of multiple dedicated pieces of equipment, such SDRs are potentially less expensive to manufacture, are lighter, require less space, less power to operate, and potentially require less total cooling air.
Some details and advantages of prior art SDRs are set forth in U.S. Pat. No. 4,658,359, entitled “METHOD FOR MANAGING REDUNDANT RESOURCES IN A COMPLEX AVIONICS COMMUNICATION SYSTEM,” U.S. Pat. No. 5,859,878, entitled “COMMON RECEIVE MODULE FOR A PROGRAMMABLE DIGITAL RADIO,” U.S. Pat. No. 5,867,535, entitled “COMMON TRANSMIT MODULE FOR A PROGRAMMABLE DIGITAL RADIO,” U.S. Pat. No. 5,909,193, entitled “DIGITALLY PROGRAMMABLE RADIO MODULES FOR NAVIGATION SYSTEMS,” and U.S. Pat. No. 6,072,994, entitled “DIGITALLY PROGRAMMABLE MULTIFUNCTION RADIO SYSTEM ARCHITECTURE.”
Although avionics systems that include SDRs have the earlier-mentioned advantages over systems with dedicated pieces of equipment, in general, current avionics systems carry unutilized or under-utilized redundant equipment to meet function availability and continuity requirements during the phase of flight (dispatch, en-route, approach, etc.) where the function is used. Having substantial redundancy of limited-purpose equipment can burden the airplane infrastructure resources.